Electrode mount



March 14, 1939. N, H. GREEN 2,150,323

ELECTRODE MOUNT Filed Jan. 29, 1938.

INVE R- ATTO Y;

Patented Mar. 14, 1939 by mesne assignments, to Radio Corporation of America, New York, N. Y., a corporation of Delaware Application January 29, 19 38, Serial No. 187,639

4 Claims.

My'invention relates to electron discharge devices,. more particularly to improvements in means to support and insulatingly space the electrodes in such devices.

Radio tube electrodes having side rods are often, mounted. with the side rods extending through perforation in insulating spacers, such as mica or ceramic discs or plates and the spacers are secured to the side. rods by fasteners, such as hollow rivets stapled in the spacer perforations or bent pieces of wire clinched at their ends in holes in the spacers and welded to the side rods. The usual fasteners prevent the spacers from slipping along the side rods, but do not prevent tilting or twisting and buckling of the spacers on the side rods. Fasteners which are riveted or stapled by machine in the spacers before the electrode mount is assembled often crack or fracture the spacers at the places where clinching takes place.

An object of my invention is improved means for supporting and spacing the electrodes in an electron discharge device.

A further object of my invention is improvements in means for supporting'and spacing electrodes which rigidly join the electrode spacers to their supporting side rods and prevent tilting or twisting movement of the spacers.

A still further object of my invention is means for attaching electrode spacers to supporting side rods which will not stress or fracture the spacer, and which are inexpensive to manufacture and assemble.

A complete understanding of my invention and its varied applications may be obtained by referring to the following detailed description of one embodiment of my invention and the accompanying drawing in which:

Figure 1 is a view of an electrode assembly embodying my invention,

Figure 2 is a detailed view of my improved side rod-to-spacer fastening means, and

Figure 3 shows how my improved fastening means is assembled in an electrode assembly.

The electrode assembly shown by way of example as a full wave rectifier in Figure 1 and embodying the characteristic features of my invention comprises cathode I and coaxial anodes 2 and 3 supported on rigid support members such as side rods 4 and 5 embedded at their lower ends in the press of a re-entrant stem to envelope 6. Parallel spacers l and 8 of insulating material such as mica or ceramic steady the electrodes and are joined to the side rods by my improved clips or fastening means 9 and iii. A radially extending fin on each anode is joined to its spacer by a strap H and is fastened to one side rod, preferably by spot welding. To prevent bodily rotation of the anode about its side rod, an ear or extension l2 opposite the side rod engages a slot in'the mica.

The distance between thesurface of the oathode I and the inner wall of the anodes is commonly as small as .015 inch. Grids in some tubes are often spaced only .004 inch. The electrodes accordingly,must' be accurately fixed in manufacture so that 'no movement between them may take place during use. To prevent twisting or displacement of either anode and a possible short circuiting contact with the cathode, I provide fastening means according to my invention for bracing the spacers against twisting, buckling or deformation and for rigidly fixing the plane of the spacers normal to the side rods. My improved fastening means or clip, best shown in Figure 2, comprises a relatively long flat strip of metal 13, such as nickel, with one face attached intermediate its ends preferably by weldingto the side rod to form a cross arm or brace against the edge of which the face of the spacer is pressed. To firmly hold the spacer against said edge, to stiffen the spacer and to prevent tilting of the spacer out of the plane normal to the side rods, tabs M on the strip extend through openings in the spacer and are preformed with right angle bends or elbows so as to be perpendicular to the plane of the strip and hold the spacer firmly against the adjacent edge of the strip.

In assembling the electrodes of Figure 1 the cathode and anodes are preferably placed in a jig, straps ll Welded in place, anode fins welded to the side rods, and the cathode inserted in its coaxial position in the anodes. My improved spacer-to-side rod clips are fixed in place by inserting tabs l4 through openings in the spacers, as shown in Figure 3, and drawing the flat face of the strip [3 toward the side rod by welding electrodes I5. When the face of strip l3 comes into contact with its side rod a current conveniently welds the strip and side rod throughout the line of contact across the strip. To gently yet firmly hold spacer 8 against the edge of strip I 3, the bend in tab I4 is formed a. distance equal to or slightly less than the thickness of the spacer. As strip I3 is forced toward side the tab may be at an angle slightly less than 90 with the plane of strip l3.

While the mica is firmly held in place by my improved fastening means, it does not dig into or fracture the spacer, characteristic of the usual clinching staple or rivet. Thin mica spacers, for example, frequently shred and split when dented by the usual stapling machine. My improved fastening means rigidly fixes the plane of the spacer normal to the side rod, braces the spacer against twisting, buckling and deformation and is inexpensive to manufacture and easy to assemble. i

I claim:

1. In an electrode assembly the combination of an insulating spacer, a rigid support member for the spacer passing through the spacer, a flat metal strip, said strip being secured on one side to said support member with one edge of said strip bearing against one side of said spacer, metal tabs on the strip bent normal tothe plane of the strip and extending to and bearing against the other side of said spacer to hold the spacer in contact with said edge of the strip.

2. In an electrode assembly the combination of an insulating spacer having three openings, a rigid support member passing through one of said openings and a flat metal strip secured to said member with one edge bearing against one side of said spacer, two spaced metal tabs on said strip in registry with the other two of said openings, each tab extending through one of said other openings and bent at right angles to the plane of said strip to bear against the other side of said spacer, the spacing between the bent of each tab and the adjacent edge of said strip being no greater than the thickness of the spacer.

3. In a radio tube mount the combination of a plurality of electrodes at least one of said electrodes having a side rod, a mica spacer for the electrodes having a perforation to allow said mica to be positioned adjacentthe end of said electrodes with said side I rod passing therethrough, a flat metal strip, the side of said strip being joined intermediate its ends to said side rod with its edge bearing against the face of said spacer, and tabs on the ends of said strip perpendicular to the plane of said strip engaging and holding said spacer against said edge.

4. An electrode assembly comprising a plurality of tubular coaxial electrodes supported between two spaced parallel insulating spacers, side rods extending transversely through said spacers and. joined to said electrodes, a metal clip forfixing one side rod to one of said spacers comprising a flat metal strip joined to the side rod with one edge bearing against one side of said spacer, tabs on the ends of the strip extending through the space-rwith a right angle bend spaced from said edge of the strip a distance no greater than the thickness of the spacer to firmly hold the spacer against said edge.

NORVAL I-I. GREEN. 

